how do I get my g.e.d

That is wrong, You can obtain your G.E.D! I Did!
It is different from state to state, a lot of communities have adult basic education programs in place to aid in the compleation of your ged. My wife has her GED my father just got his, its possible. If this is what you wish to do, if you are no longr in school. However, for simply an alturnative as finishing school... Because you do not wish to invest the time, you may regret it as even though itis supposed to be an equivilent to highschool, and statisticlly speaking you must score higher than the graduationg highschool class avrage state wide, people tend to frown on a GED.
What state do you live in, I would be happy to do some research for you.